Fix incorrect command to generate public key for end-to-end encryption

[BewareMyPower]

The command in the document does not work for OpenSSL 1.1 or 3.2.

$ openssl rsa -in test_rsa_privkey.pem -pubout -outform pkcs8 -out test_rsa_pubkey.pem
rsa: Bad format "pkcs8"
rsa: Invalid format "pkcs8" for option -outform
rsa: Use -help for summary.
$ openssl --version
OpenSSL 3.2.0 23 Nov 2023 (Library: OpenSSL 3.2.0 23 Nov 2023)
$ /opt/homebrew/opt/[email protected]/bin/openssl rsa -in test_rsa_privkey.pem -pubout -outform pkcs8 -out test_rsa_pubkey2.pem
rsa: Invalid format "pkcs8" for -outform
rsa: Use -help for summary.
$ /opt/homebrew/opt/[email protected]/bin/openssl version
OpenSSL 1.1.1w  11 Sep 2023

• doc
• doc-required
• doc-not-needed
• doc-complete

[tisonkun]

Shall we update this command for other old docs version?

[lhotari]

Shall we update this command for other old docs version?

@BewareMyPower Any chance to handle that in this PR?

[BewareMyPower]

Sorry I missed the response before, I will update it soon.

[BewareMyPower]

@tisonkun @lhotari I updated docs for 3.0.x and 3.1.x as well because I think we won't maintain 2.x anymore. BTW, I reduced the unnecessary changes of the order of command options.